Planar Coherent Waves observed in Magnetospheric Multi Scale Fast Plasma Imager Phase Space Measurements: Part 2
Presentation Type
Poster
Presenter Format
Virtual Meeting Talk
Topic
Fundamental Processes in Comparative Magnetospheres
Start Date
12-5-2022 4:00 PM
Abstract
Various wave vector estimation methods like Bellan’s method, multi-phase component analysis, and k-filtering with DivB=0 rely on the assumption that one dominant wave vector exists per frequency bin. They can’t resolve multiple wave fronts in a bin. Wave distribution function analysis could be used to tackle this. However, in this study we explore a different route where the response of phase space density (PSD) of the ions and electrons due the superposition of two wave vectors are visualized in phase space. A plasma wave is characterized by the cyclic exchange of energy between particles and fields that compose the wave mode, along with possible resonant interactions. The response of phase space to both of these interactions is a function of wave vector direction. Burst mode MMS-FPI measurements with a Nyquist frequency of 3 Hz for the ions and 17 Hz for the electrons will be used in this study, allowing the investigation of waves below these frequencies. The focus will be on waves in the ion cyclotron frequency range. First, we will use linear theory to explore how FPI PSD should respond to one and two wave vectors as function of wave amplitude and PSD one count level, exploring various projections of PSD. Then we will re-analyze a kinetic Alfven wave (KAW) event with oblique propagation in the magnetopause boundary layer for which the FPI PSD is highly unstable to field aligned ion cyclotron waves (ICW) to see if this event could actually be explained as a superposition of an ICW and its reflection.
Planar Coherent Waves observed in Magnetospheric Multi Scale Fast Plasma Imager Phase Space Measurements: Part 2
Various wave vector estimation methods like Bellan’s method, multi-phase component analysis, and k-filtering with DivB=0 rely on the assumption that one dominant wave vector exists per frequency bin. They can’t resolve multiple wave fronts in a bin. Wave distribution function analysis could be used to tackle this. However, in this study we explore a different route where the response of phase space density (PSD) of the ions and electrons due the superposition of two wave vectors are visualized in phase space. A plasma wave is characterized by the cyclic exchange of energy between particles and fields that compose the wave mode, along with possible resonant interactions. The response of phase space to both of these interactions is a function of wave vector direction. Burst mode MMS-FPI measurements with a Nyquist frequency of 3 Hz for the ions and 17 Hz for the electrons will be used in this study, allowing the investigation of waves below these frequencies. The focus will be on waves in the ion cyclotron frequency range. First, we will use linear theory to explore how FPI PSD should respond to one and two wave vectors as function of wave amplitude and PSD one count level, exploring various projections of PSD. Then we will re-analyze a kinetic Alfven wave (KAW) event with oblique propagation in the magnetopause boundary layer for which the FPI PSD is highly unstable to field aligned ion cyclotron waves (ICW) to see if this event could actually be explained as a superposition of an ICW and its reflection.
